Clinical Trial: Mechanisms of Insulin Facilitation of Memory

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Mechanisms of Insulin Facilitation of Memory

Brief Summary: The study described in the present application will test the hypothesis that insulin mediated facilitation of memory in Alzheimer's disease (AD) is achieved through enhanced glutamatergic neurotransmission due to improvements in cerebral glucose metabolism. The effect of a single dose of intranasal insulin on memory and cerebral glutamate concentrations in adults with mild AD or amnestic mild cognitive impairment (aMCI), the presumed prodromal phase of AD will be studied. Successful completion of this study may set the stage for a larger-scale treatment trial of intranasal insulin for adults with memory disorders. However, the use of insulin in this manner at this point in time is purely experimental.

Detailed Summary:

The specific aims of this project will be accomplished through a cross sectional repeated measures design in which 15 participants with mild AD or amnestic MCI will undergo assessments of brain structure and function 15 minutes after a single dose of insulin (20 IU) or placebo. Insulin and placebo conditions will be counterbalanced across participants.

Intranasal insulin or placebo administration: Saline and insulin (NovoLog) will be ordered though the UT Student Health Services Pharmacy (Sharon Roberson, Chief Pharmacist) and stored at 4°C, according to standard pharmacy protocols. Three ml doses of saline or insulin will be packaged in nasal spray bottles (e.g., Spectrum Pharmacy Products bottles 969-17404P and actuators 551-24362P) designed to deliver 100μL dose with each spray. A total volume of 200μL will be delivered during each administration (one 100μL dose in each nostril).


Sponsor: University of Texas at Austin

Current Primary Outcome: Cerebral Glutamate Concentration [ Time Frame: 15 minutes post insulin or placebo administration ]

Glutamate concentration was expressed as the ratio of glutamate to creatine. This was determined using magnetic resonance spectroscopy (MRS), a magnetic resonance technique that uses the same equipment as magnetic resonance imaging (MRI), but allows researchers to extract information about the concentrations of various neurochemicals of neurobiological significance.


Original Primary Outcome: Cerebral Glutamate Concentration [ Time Frame: 15 minutes post insulin or placebo administration ]

glutamate concentration will be measured non-invasively using 1H MRS


Current Secondary Outcome: Memory [ Time Frame: 15 minutes post insulin or placebo administration ]

Memory performance was assessed using delayed recall (number of units recalled) on the Wechsler Memory Scale (WMS-IV) logical memory (story recall) test. Scores represent a sum of recalled units of two different stories after a 30 minute delay. Total scores range from 0 to 50 (0-25 for each story) with higher scores reflecting better memory performance


Original Secondary Outcome: cognitive performance [ Time Frame: 15 minutes post insulin or placebo administration ]

memory, executive function, mental status


Information By: University of Texas at Austin

Dates:
Date Received: June 15, 2010
Date Started: July 2010
Date Completion:
Last Updated: October 30, 2014
Last Verified: October 2014